Modifier keys ( Shift etc.) can be monitored via mousemove etc. Or some key is simply kept held, while the user is switching to another tab or application with the mouse, then released outside our page. Coming back to the browser page, it'll still think the key is held, though it was released in the meantime. If the user alt-tabs away, or uses a key gesture to open a new browser window or tab, then a keydown will be registered, which is fine, because at that point it's impossible to tell if the key is something the web app is monitoring, or is a standard browser or OS shortcut. Anything else will also fire the function, like gamepad.I scanned the above answers and the proposed keydown/ keyup approach works only under special circumstances. UserInput.InputBegan:Connect(inputR) - So we can fire the function when any key/mouse is pressed. If inputObject.Ke圜ode = Enum.Ke圜ode.R then - Replace 'Ke圜ode.R' with any other key, for example, left shift is 'Enum.Ke圜ode.LeftShift'. If inputObject.UserInputType = then - So we know that the player is holding down a key on their keyboard instead of a fake one local UserInput = game:GetService('UserInputService') - So we can fire the function below I Added more comments to make more clear. Now test the key you would like to be pressed. Now make sure the user has a keyboard, so no weird errors occur. If gameProcessedEvent then return end - I did it this way so it doesn't take up space. Now insert a simple if statement inside the local function with a return. Local function inputR(inputObject, gameProcessedEvent) Remove the print function and replace it with this: local UserInput = game:GetService('UserInputService') - So we can fire the function below

First, insert a LocalScript into the StarterPlayerScripts in the StarterPlayer.

Check if key is held down roblox